I am prepping my house for sale, and it had a pretty badly cracked sidewalk and driveway. Its a pretty common problem, with a straight forward solution: bust out the old concrete and pour new. And it is great that a problem so common has a sustainable solution: fly ash concrete. Fly Ash is a waste product that comes from coal fired power plants. Now coal fired power plants are bad, and the sooner we get rid of them the better, but we do not have the infrastructure in place to stop burning the stuff, and we wont for some time. Around 100-110 million tons of Fly Ash are produced annually, often dumped here or there, with not much attention paid to it until things like this happen.
But millions of tons of fly ash can be used in concrete. The ash replaces Portland Cement, and cement production releases millions of tons of CO2 into the air every year – you have to heat limestone up to 1300 degrees to turn it into cement, and that fire creates the CO2. Concrete is the most common man made construction material used in the planet – 100s of millions of cubic yards are used each year. Every time someone does something as simple as a driveway or sidewalk repair, they can help out the environment by using some fly ash. My own little job used 4.5 cubic yards of concrete, with 15% of the cement replaced by fly ash from Bode Concrete of San Francisco’s sidewalk mix. My man Sal “Rocky” DeGuarda did the job for me, I recommend him for jobs in San Francisco.
You have to ask for it, and your contractors will get it for you. People want to be responsible, because we all want a better world for our kids.